Radwanska vs Errani, Azarenka vs Li - the winners of those will be the other two semifinalists.
WTA Staff

ISTANBUL, Turkey - Sara Errani wrapped up the winners on Day 3 of the TEB BNP Paribas WTA Championships - Istanbul 2012, outdoing Samantha Stosur and setting up a back-to-back showdowns for the semifinals on Friday.

Watch video highlights from Istanbul right here on wtatennis.com!

With Petra Kvitova pulling out of the tournament a day before due to a viral illness, Stosur stepped in as an alternate to take Errani on - but it was not to be for the Australian, whose aggressive game plan paid dividends in the second set but went wild in the third set, Errani cruising to victory, 63 26 60.

"In the beginning she was making a lot of unforced errors, but in the second set she was playing amazing," Errani said afterwards. "I was just trying to stay focused and aggressive today and I think the third set was better for me."

The third set was truly one way traffic, with Stosur saving the first match point against her with a big backhand winner but double faulting on the next one - it was her seventh double fault - and 49th unforced error - of the match.

"I really wanted to try and play a good match tonight and be at least one match up, but obviously the result wasn't quite that way," Stosur said. "It was a little bit up and down - in the second set I got off to a good lead and then was able to hold onto that and win the set, and then I had a break point in the first game of the third and missed a return, and then it was like all the energy went out of me.

"I certainly dug myself into too much of a hole to try and get out."

"Sam is a great player but I was ready today," said Errani, who kept her errors down at 15. "I'm happy I won and that I'm still in the tournament - I hope I can play well tomorrow too and maybe win, I don't know, we'll see how it goes."

Errani was 0-28 against Top 10 players going into the French Open this year but has gone 5-4 since, two of those five wins coming against Stosur (one there and one here), two against Angelique Kerber (one there and one at the US Open) and one against Marion Bartoli (at Tokyo [Pan Pacific]).

But she still has a monkey on her back - she is 0-22 against Top 5 players in her career, something she'll have to overcome as she takes on World No.4 Agnieszka Radwanska on Friday - the winner of that match will qualify for the semifinals as No.2 in the White Group, behind Maria Sharapova.

"She's a very strong player," Errani said of Radwanska. "I know her and we have played before. It will be a tough match and we will see what happens."

That match is second on, and the third match on will also determine a semifinalist - Victoria Azarenka and Li Na will square off, the winner of that match qualifying for the semifinals as No.2 in the Red Group, behind Serena Williams (Azarenka and Li both played on Thursday as well - read about Azarenka's loss to Williams here and Li's win over Kerber here).

The first match of the day pits Sharapova against Stosur and will not affect the standings in the White Group or who qualifies for the semifinals.

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